Epoxy resins have been used in various fields such as coating compositions, sealing agents, adhesives and the like, because of their excellent properties, in particular, their high adhesion. However, most of conventionally used epoxy resin compositions are two-packed compositions consisting of a main agent and a curing agent. Since the curing reaction starts immediately after mixing the main agent and curing agent, the two-packed epoxy resin compositions have a very short pot life, resulting in poor workability.
Method were proposed for extending the pot life, for example by adding a latent curing agent such as blocked isocyanate to an epoxy resin. However, the latent curing agent is inherently of a heat-curing type, and is not practically usable for curing by ordinary temperature drying. The present applicant proposed in Japanese Examined Patent Publication No. 32231/1987 a method for preventing corrosion using a coating composition comprising an epoxy resin, a ketimine compound and a dehydrating agent. However, the composition, when used as a two-packed type, has poor drying characteristics and a very low curing rate, although having a prolonged pot life. On the other hand, when the composition is used as a one-packed type, it has insufficient storage stability.